I've been using my g flex all day for emails, writing notes, calendar and note browsing and music. At 5.40pm it's showing 66% charge (charged overnight and started using at 7am). Typically by this stage my old s4 would have run out; htc one about 25% left, note 3 about 30%).
In part this might be because the double tap makes it very easy to turn off when the phone is on the table and I'm not taking notes.
My favorite device for a long time!